If a player gets traded 100 gold, then the player getting gold loses 10 karma.
What this would do is make players that need some gold still able to trade for gold, but players trying to get 500,000,000,000 gold would have to have played the game enough to have at least that much karma for the trade (most gold buyers are doing it just to skip playing the game, after all).
This could also work with items assuming "real" in-game gold values could be found for the them. Though I realize most games find this difficult because the actual gold cost of the item on the AH is usually much different than what the vendor thinks.
Edited by OGF, 03 April 2011 - 02:31 PM.